Tablet grading means



V. C. HALL TABLET GRADING MEANS Oct. 15, 1957 5 Sheets-Sheet l Filed Nov. 2, 1954 vINVENTOR vlroR c. HALL vA TORNEYS` Oct. 15, 1957 v. c. HALL TABLET GRADING MEANS Filed NOV. 2, 1954 ATTORNEYS 3 Sheets-Sheet 2 FIG. 2

vlcToR c. HALL Oct. 15, 1957 v. c. HALL 2,809,751

TABLET GRADING MEANS Filed Nov. 2. 1954 3 Sheets-Sheet l5 x-RAY souRcE /33 FIG. 5

VICTOR C. HALL i EY fum l www WW aM/79d ATTO R N EYS atet f TABLET GRADING NIEANS -Victor C. Hall, Media, Pa., assignor, by mesne assignments, to F. J. Stokes Corporation, Phiiadelphia, Pa., a company of Pennsylvania Application November 2, 1954, Serial No. 466,375

Claims. (Cl. 209-82) This invention relates to the classifying, grading, or selecting of small solid objects such as pills, tablets, capsules, briquettes, and the like, hereinafter called tablets, and has for its object the provision of an improved method and apparatus for these purposes. More particularly, the invention is concerned with the selection of perfect or acceptable tablets from the imperfect or objectionable tablets by means of a combination X-ray, electronic, and mechanical means.

The invention is advantageously applicable to the classification of medicinal tablets, such as those formed by compression in a die. Tablets containing a medicament core tablet with a surrounding coating can be classilied to reject tablets having a missing core, an imperfect core, or an imperfect coating, for example, one too thick or too thin, or a combination of these imperfections. The invention may be used to reject tablets formed of inadequate or imperfect materials or having imperfect form, density, and the like.

This invention utilizes the passage of X-ray impulses through the tablets while they are moving through the X-ray beam in rapid succession, and other electrical devices responsive to variations in the intensity of the impulses to actuate selecting means.

My invention provides a process of moving a succession of tablets at relatively high speed through an X-ray beam while securing the tablets in precise alignment with the X- ray beam and controlling the movement of the tablets with reference to the impulse timing of the beam so as to send several separate impulses through different parts of the tablet, and utilizing any of these impulses to eect a rejection of a defective tablet. In one embodiment of the invention, the tablets are released from the moving and securing means and a jet of gas or air is directed against the falling rejected tablets in a precisely timed interval after said release to remove them from the other tablets.

My invention provides an improved apparatus for moving a succession of tablets from a tablet supply source at controlled speed through an X-ray beam comprising an endless carrier to which are attached tablet receiving and securing means, means for directing several separate X- ray impulses through different parts of each tablet, and means actuated by the X-ray impulses for removing rejected tablets. In a preferred embodiment 0f my invention, l attach to the links of an endless chain a plurality of tablet receiving and securing lingers which extend outwardly in a horizontal plane and which travel over a fiat horizontal support or table. Each pair of adjacent. lingers comprises a pocket for precisely securing a tablet and holding it in an exact position while traveling, preferably inV a straight line, through the X-ray beam. The chain is in operative connection with at least one chain sprocket and also travels over another sprocket or a pulley, and one of the sprockets is located near a tablet feed means. The fingers are each so connected to a link of the chain that they are held normal to the chain links,

the adjacentftngers being close to each other where the chain travels in astraight line, and when the chain Ypasses around a sprocket, the fingers assume radial positions which result in the adjacent fingers becoming spread apart an appreciable distance depending on the radius of the sprocket and the length of the fingers. The tablet feed means is located above the sprocket and the pockets of the lingers so that as the spread-apart ngers pass under fthe feed means a tablet fallsl by gravity between the adjacent ngers and onto the at support. Each tablet is engaged by the pocket portion of the leading edge of one finger and is carried in this position until the chain leaves the sprocket. After the chain leaves thersprocket vand begins to travel in the straight line towards the X-ray beam, the adjacent lingers are closed and this resultsin the tablet being secured in the pocket formed by complementary recesses in the leading edge of one finger and the rearward edge of the adjacent iinger.4 One of the important features of the invention is that the appreciable space between the lingers while traveling over the sprocket and under the tablet supply makes it possible to drop the tablets by gravity feed while the chain is traveling at appreciable speed and thereafter to close the fingers to confine the pockets in precise alignment while traveling through the X-ray beam.

At a suitable place Where the chain travels in a straight line after leaving the sprocket, the tablets pass over an opening in the support through which X-ray impulses are passed through each tablet, and after passing the X- ray beam, they fall through a hole in the support and past a .nozzle through which an air blast can be directed against rejected tablets to remove them from the acceptable tablets.

These and otherobjects of the invention will bevbetter understood after considering the following discussion taken in conjunction with the accompanying drawings, in which:

Fig. l is a diagrammatic illustration of the Hytall Automatic Unit modied for adaptation in the apparatus of the invention;

Fig. 2 is a fragmentary plan View of apparatus embodying the invention;

Fig. 3 is a fragmentary side elevation at the feed end of the apparatus taken at 3-3 of Fig. 2;

Fig. 4 is a View, partly in section, at 4--4 of Fig. 2, and

Fig. 5 is a sectional side view of a modified device for timing the action of the air jet directed against defective tablets.

The apparatus illustrated in Fig. l consists largely of the well known General Electric Hytaiill Unit, the operation of which is well known and will not be described in detail. For convenience of illustration, the phototube and light source are shown displaced to the left. Actually they are in direct line with the X-ray beam shown in broken lines from the X-ray target to the crystal detector as shown in Fig. 4. The electrical connections 1, 2 and 3 from the reject relay stage are connected to a solenoid air valve 4, the tube 5 is connected to a source of air under pressure, and the tube 6 is connected through coil 7 to the jet end 8.

Fig. 2 illustrates lan advantageous embodiment of apparatus of my invention comprising a tlat horizontally disposed support 10 in the form of a metal plate. The chain sprockets 11 and 12 and 4the idler sprocket 13 are mounted directly over the support, sprocket 12'being connected to a motor to drive the link chain 14. In one embodiment of the invention especially suitable for the grading of medicinal tablets, sprocket 11 is 4 inches in diameter, sprocket 12 51/2 inches `in diameter, and the chain has 46 identical links 15,- each having a linger -16 attached thereto. .Each finger is about 21/4 inches long,

3A inch wide, and is attached to an vextension 17 of the 'linkby a plate n1'8which vis'held on `the'fingerby screws 'This rate of travel will handle about 400 tablets per minute.

The leading edge of each `.linger has a tablet-pocket portion 2'2 and the rearward edge has a smaller tabletpoclretz-portion 23 which, when the adjacent fingers are together, make secure contact with the tablet T. Each fingerhas a cutout portion Y24 which leaves an area 25 of critical width, thefunction of which will later be described. The lingers also have a thinned end portion nea-r thepocketsto `permit passage under the plate 26 as they approach-the feed tube 27 which prevents them from striking this tube`which is located very close to the upper surfaces of the fingers.

As the fingers pass over the sprocket 12, they assume Vthe radial positions shown and the pockets are approximately 1 inch apart so that with a chain traveling at a relatively high rate there is amplespace and time for a tablet to fall from the tube 27 and be picked up by the pocket 22V in the leading ,edge vof the finger. The apparatus proportioned as just described .can operate at speeds up to 900 tablets per minute. While thetablets ,travel at a considerably greater speed-around the sprocket 12 thanpast the X-.ray beam, nevertheless the spreadapart position of the fingers permits the tablets to be dropped between the fingers in a highly efficient manner.

While the tablets can be supplied by any suitable means, l prefer to use a bent tube Z7 which orients the tablets T' automatically to a fiat position at .the outlet end as more ,fully described in my copending application Serial No. 568,215, filed February 28, 1956. VWhile any suitable device may be used to feed tablets into the tube 27, it is advantageous to feed tablets to this tube through a device 30 known as a Syntron YVibratory Elevator, for example, the device known as Type 'EBO-D Style FO91226.

It will be noted that the idler 13 is set to maintain the required tension in the chain, and that the chain travels in a straight line on the opposite side to carry the tablets T secured ybetween adjacent fingers over slot 31 in the support 10, and that the cutout portion 24 and section 25 of the fingers travels over the slot 32 inthe support. 1

As best shown in Fig. .4, the X-ray source 33 is located above the support and the traveling fingers, and the X-ray beam 34 passes directly through the tablet and `slot 31 into contact with the sensitive crystal 35. The phototube Y3,6, light source 37 and slot 32 are in direct alignment .and in the same plane as the X-ray beam 34.

The solenoid operated air valve 4 controls the ow of air from tube 5 through tube 6, ,coil 7 andthe nozzle 8 which is located beneath kthe 4hole 38 in the support. The coil `7 has such length that the blast of air through nozzle `8 is delayed sufi'iciently to permit the tablet to fall through hole 38 because the solenoid valve is opened instantly and .while the tablets are over the slot 31. Instead of using gas and a nozzle to reject the imperfect tablets, l may modify the solenoid valve 4 to operate a mechanical device for this purpose, 'or other suitable mechanical means.

Fig. 5 illustrates a modified lblast-retarding means for use in place of the coil 7 to retard the fiow of air from the solenoid Vvalve 4 to thenozzle 8. The enlarged tube `,4 is connected to one .side of tube `6 andlhas a-relativel-y large interior chamber 4 1. Y One end Vportionof dthe tube 4 40 is threaded to receive a threaded plug 42 which is attached by the coupling 43 to the tube '6. By adjusting the position of plug 42 in the tube 40, the size of the chamber 41 can be varied and, accordingly, the time of delaying the yblast of air through nozzle 8.

When it is desired to grade tablets, for example, by passing four X-ray impulses .through each tablet, any one of which can effect a rejection, the kwidth of the section 25 of each finger is proportioned with respect to the width of the tablet so thatas thesection passes Vover the slot 32 and shuts off the light passing therethrough to the phototube the shutter relay is operated to open the shutter 40 so that during that interval four X-ray impulses will pass through the tablet. As the tablet is moving at a rapid rate, say, from 400 to 900 passing over the slot per minute, the separate impulses are spaced across the diameter of the tablet.

if the tablety is of proper form and composition, lthe signal from the crystal detector is not of sufficient amplitude to cause conduction ,of the gated amplifier, the tablet detection circuit will Vnot be triggered, the grid cathode potential will remain at its most negative cutoff value, and the reject relay stage will not be actuated to cause the solenoid valve 4 to open and vadmit vair to the nozzle 8.

If the composition or form of the tablet is not as required, the X-ray impulses impinging on the crystal detector will cause the signal from the crystal to be of such amplitude as to cause condition of the gated amplifier in the associated amplifier and the tablet reject stage will be triggered and the grid-cathode bias thereof will change to its least negative cutol value with the Vresult that a reject pulsation willcause the reject relay stage to actuate the solenoid valve and cause a blast of air to be dischargedthroughinozzle 8.

The reject action openingthe air valve 4 occurs almost instantly and while the tablet is virtually Aover slot 31. The :tablets must travel the short distance to hole 38 and drop through in order to be removed from the operation. As the tablets fall by gravity through the hole 38 and pass beneath the support 10, they fall past nozzle 8. All those tablets that are acceptable fall into a certain receptacle. When the solenoid valve is opened by a reject signal, the air blast is directed against the falling tablet Aand blows it to a separate receptacle.V Since, as stated above, the solenoid valve is opened while the tablet is still on thev support 10, the efect o f the blast is delayed either by the coil 7 or the device shown in Fig. 5 so that the blastof air strikes the tablet while it is falling in front of the nozzle.

The traveling fingers may pick up dust or particles of broken tablets and to remove these materials from the traveling chain and tingers the fingers pass over a relatively large hole 44 in the table through which they fall.

l claim:

l. The combination with an X-ray sorting device including a source of X-ray beam, a sensitive crystal Vfor receiving the X-ray beam, a light sensitive means for regulating the period ,of X-ray exposure, and amplifier means for utilizing impulses from the sensitive crystal which comprises a platform for supporting tablets and an endless chain, said chain having links and a tablet-carrying linger connected to each link, at least one sprocket overwhich said chain travels, said platform, chain, ngers, sprocket and pulley being horizontally disposed, 'the back edge of each finger having a recess which mates with a recess on the leading edge of the adjacent finger forming a pocket for receiving `and securely'holding a tablet, a tablet feed means located near the sprocket, said sprocket being of such diameter that as the chain passes thereover the fingers assume radial positions and the adjacent fingers spread apart very appreciably at the feed means whereby the opening between the iingers permits .the tablets to be fed therein and picked up by the recess in the leading ledge of the nger while the chain is traveling at an appreciable rate of speed, a portion of said chain being arranged to travel in a straight line after passing the sprocket with the adjacent fingers in close contact, an opening in the platform Where the chain travels in a straight line for X-ray impulses of the beam to pass through each tablet held in the lingers and into contact with the sensitive crystal, the light-sensitive means being arranged to regulate the time X-ray impulses are passed through each tablet to the sensitive crystal, an opening in the platform through which tablets fall after passing the X-ray beam, an air jet located near the opening where the tablets fall, and means operatively connecting the amplier and the air jet to release a blast of air against tablets rejected by the X-ray impulses and remove them from the other tablets.

2. Apparatus for rapidly moving a succession of tablets through a sorting device to reject imperfect tablets which comprises a horizontally disposed platform, an endless link-chain which travels over at least one sprocket mounted directly above the platform, a nger connected to each link extending outwardly from the chain and directly over the platform, a recess in the leading edge and another recess in the back edge of each linger which recesses form a tablet pocket when the adjacent ingers are close together, a sorting device located in an operative position near the platform, said chain being disposed to travel in a substantially straight line at said sorting device at which place the adjacent ngers are close together and the tablet-s are securely held in the pockets, said platform having an opening through which all the tablets fall after passing the sorting device, said sprocket being of such 30 diameter that as the chain travels thereover the fingers assume radial spread-apart positions with appreciable spaces between the recesses forming the pockets, and a tablet feed means arranged to insert tablets between the spread-apart iingers which are picked up by the recess in the leading edge of one finger and carried to the place where the ngers close.

3. Apparatus according to claim 2 which comprises means beneath the opening in the platform in operative connection with the sorting device for directing an air blast against rejected tablets to remove them from the other tablets.

4. Apparatus according to claim 2 in which said sorting device includes a light sensitive means, each nger having a hole therein through which light passes to operate the light sensitive means which controls the operation of the sorting device.

5. Apparatus according to claim 2 in which said tablet feed means is operated by gravity.

References Cited in the le of this patent UNlTED STATES PATENTS 2,532,644 Robinson Dec. 5, 1950 2,659,012 Bromberg et al Nov. l0, 1953 2,659,823 Vassberg Nov. 17, 1953 2,679,317 Roop May 25, 1954 FOREIGN PATENTS 722,384 Great Britain Jan. 26, 1955 

